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United States Patent |
5,701,874
|
Sari
,   et al.
|
December 30, 1997
|
Balanced valve control member for exhaust gas recycling
Abstract
A control valve for the recycling of exhaust gas from an exhaust gas
channel to an air inlet channel of the engine, wherein a valve member of
the valve opens and closes a valve opening between the exhaust gas channel
and the air inlet channel. An electromagnetic control unit acts on the
valve member to open the valve and a spring biasses the valve to a closed
state. The valve member has a closure portion for closing the valve and is
formed with a balancing section spaced from the closure portion and formed
with a cross-sectional area equal to that of the closure portion so that
the air pressure in the inlet channel applies equal and opposite forces on
the balancing section and the closure portion whereby the valve is
balanced and not subject to pressure variations in the air inlet channel,
such as due to turbocharging.
Inventors:
|
Sari; Osman (Gravenbroich, DE);
Blank; Helmut (Bornheim, DE)
|
Assignee:
|
Pierburg AG (Dusseldorf, DE)
|
Appl. No.:
|
633890 |
Filed:
|
April 17, 1996 |
Foreign Application Priority Data
| Apr 25, 1995[DE] | 295 06 928.7 |
Current U.S. Class: |
123/568.26; 60/605.2; 251/129.07 |
Intern'l Class: |
F02M 025/07 |
Field of Search: |
123/568,569,571
60/605.2
251/282,129.07
|
References Cited
U.S. Patent Documents
3799131 | Mar., 1974 | Bolton | 123/568.
|
4662604 | May., 1987 | Cook | 123/568.
|
4852853 | Aug., 1989 | Toshio et al. | 251/129.
|
4909440 | Mar., 1990 | Mitsuyasu et al. | 251/129.
|
5255659 | Oct., 1993 | Choma | 123/568.
|
5333456 | Aug., 1994 | Bollinger | 123/568.
|
5497975 | Mar., 1996 | Achmad | 251/129.
|
5511531 | Apr., 1996 | Cook et al. | 123/568.
|
Foreign Patent Documents |
7227371 | Mar., 1973 | FR.
| |
4204434 | Aug., 1993 | DE.
| |
4410487 | Mar., 1995 | DE.
| |
2250801 | Jun., 1992 | GB.
| |
Primary Examiner: Wolfe; Willis R.
Attorney, Agent or Firm: Ladas & Parry
Claims
What is claimed is:
1. A control valve for the recycling of exhaust gas to an internal
combustion engine in which the valve controls flow of the exhaust gases
from an exhaust gas channel to an air inlet channel of the engine, said
control valve comprising a valve member for opening and closing a valve
opening between the exhaust gas channel and the air inlet channel,
electromagnetic control means acting on said valve member to open said
valve opening, spring means biassing said valve member to close said valve
opening, a chamber communicating with said air inlet channel, said valve
member including a closure portion for closing said valve opening, said
valve member further including a balancing section spaced from said
closure portion, said closure portion and said balancing section being
exposed in said chamber to the air pressure in said inlet channel and
being opposed to one another so that forces developed by pressure of the
air in said air inlet channel acts on said valve member in opposite
directions to balance said valve member.
2. A control valve as claimed in claim 1, wherein said balancing section
and said closure portion of said valve member have surfaces exposed in
said chamber which have substantially equal areas to equilibrate the
forces acting on said valve member.
3. A control valve as claimed in claim 2, wherein said control valve
further comprises a further chamber containing said biassing means, said
further chamber being at atmospheric pressure.
4. A control valve as claimed in claim 3, wherein said control valve
further comprises a casing insertable into a bore of the engine, said
casing being provided with said chamber which communicates with said air
inlet channel and with said further chamber, said casing including a wall
separating said chambers, said balancing section of said valve member
passing through a bore provided in said wall, said valve member including
a rod portion connecting said valve closure portion and said balancing
section, said rod having a reduced cross-section compared to said
balancing section and said valve closure portion.
5. A control valve as claimed in claim 4, wherein said control valve
further comprises a guide member in said bore in said wall slidably
receiving said balancing section of the valve member.
Description
FIELD OF THE INVENTION
The invention relates to the construction of a control valve for use in the
recycling of exhaust gases to an internal combustion engine.
Such valves control flow of recycled exhaust gases to the engine.
BACKGROUND AND PRIOR ART
Such a control valve is disclosed in German application DE 42 04 434.
However, when this control valve is used in internal combustion engines
which are turbocharged, the pressure pulsations produced by the
turbocharger produce opening of the control valve when exhaust gas
recycling is not intended. In this control valve, the exhaust gas channel
and the air inlet are in communication with a common chamber of the
control valve and a valve member controls the recycling of the exhaust
gases and the air to the engine.
SUMMARY OF THE INVENTION
An object of the invention is to provide a control valve which controls
recycling of exhaust gases to an internal combustion engine which is not
subject to pressure pulsations and which can be utilized for turbocharged
engines especially having high turbocharging.
The above and further objects of the invention are achieved by a
construction of a control valve having a closure portion and a balancing
section which are subject to air inlet pressure of the engine, said
closure portion and said balancing section having equal cross-sectional
areas so that opposed forces are produced on the valve member to balance
the valve member. Thereby, the valve member is closed under the action of
a biassing spring and remains closed until the valve member is opened by
electromagnetic control means. Accordingly, there is no tendency of the
valve member to open, irrespective of said inlet pressure as, for example,
under pressure developed during a high turbocharging operation.
In further accordance with the invention, the closure portion and balancing
section are exposed to said inlet pressure in an inlet chamber formed in
the valve member, and outside said inlet chamber, the valve member is at
ambient atmospheric pressure.
BRIEF DESCRIPTION OF THE DRAWING
The sole FIGURE of the drawing shows a partial sectional view of a control
valve according to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
With reference to the drawing, therein is seen a control valve 1 used for
recycling of exhaust gases to an internal combustion engine E.
The control valve includes a casing 2 which is inserted into a bore 2'
provided in the engine E. The control valve 1 controls communication
between an air inlet channel 3 and a channel 4 leading to the exhaust gas
system of the engine.
An electromagnetic control unit 5 of the control valve 1 is secured to
casing 2 and acts to open the valve 1 against the opposition of a biassing
spring 6 when exhaust gases are to be recycled to the engine.
The valve 1 includes a valve member 20 slidably mounted in a guide member 8
for being opened and closed by the action of the electromagnetic control
means 5 and the biassing spring 6. The valve member 20 is formed with a
rod section 7 connected at its upper end to a balancing section 9 slidable
in guide member 8 and at its lower end to a valve closure element 12. The
rod section 7, balancing section 9 and closure element 12 are exposed in a
lower chamber 14 formed in casing 2. The lower chamber 14 is in
communication with inlet channel 3 so that chamber 14 is at the pressure
of the air in the inlet channel 3. The balancing section 9 and the valve
closure element 12 have respective cross-sectional areas 10 and 11 which
are substantially equal and greater than the cross-sectional area of rod
section 7. Accordingly, the forces acting on balancing section 9 and
closure element 12 due to the pressure in chamber 14 are substantially
equal so that the forces acting on the valve member 20 will be
equilibrated and the valve member will remain balanced by the pressure
irrespective of its magnitude or variations thereof. The casing 2 is
formed with an upper chamber 13 which is separated from chamber 14 by a
wall 15 provided with a bore in which the guide member 8 is secured. The
chamber 13 contains the biassing spring 6 and is at ambient atmospheric
pressure whereby the valve member 20 remains balanced and not subject to
forces due to air inlet pressure.
Accordingly, the pressure in the air inlet system, which can vary
substantially due to the action of a turbocharger, has no effect on the
opening and closing of the valve 1. The valve 1 is simple in construction
and easy to manufacture and is especially suitable for substantial inlet
pressure variation especially for high turbocharging operation.
Although the invention is disclosed with reference to a particular
embodiment thereof, it will become apparent to those skilled in the art
that numerous modifications and variations can be made which will fall
within the scope and spirit of the invention as defined by the attached
claims.
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